Low temperature dyeing of synthetic polyamide fibers



United States Patent US. Cl. 8-21 9 Claims ABSTRACT OF THE DISCLOSURESynthetic polyamide carpets and jute-backed nylon carpets are .dyed at arelatively low temperature range of 120180 F., and at a controlled pHusing specified leveling agents and buffer salts to controlled pH in therange of 5.5 to 7.0.

This invention relates to a process of dyeing synthetic polyamide fibersat low temperatures, to preparations used in the course of such dyeingand to polyamide fibers dyed by said process. The invention refers toboth continuous filaments and staple fibers and is particularlyconcerned with synthetic polyamides used in the manufacture of carpets.

At the present time polyamide carpet yarns and polyamide carpets with ajute backing are mostly dyed by disperse dyes due to their case ofapplication and good levelling properties. Disperse dyes are generallyused in alkaline bath which minimizes to a certain extent the stainingof the nylon pile by jute backing. However, disperse dyes do not haveadquate fastness to light and to wet cleaning which are required ofcarpets. To improve fastness, attempts have been made to use acid dyeswhich of course must be used in an acid bath. Under such conditions thedark colored compounds in the jute backing, such as lignins, are readilyabsorbed by the nylon carpet face. The light fastness of the absorbedstain is very poor, and when the carpets are dyed in light colors, dullshades will, be particularly noticeable. It should be also noted that atthe present time all dyeing, with disperse dyes as well as with aciddyes, is usually carried out at or near the boil, namely, at about 200F. and 212 F. Such high temperatures tend to intensify jute stainingduring the dyeing and to cause distortion of the staple nylon pile.

An object of the present invention is the provision of a dyeing processwhich will eliminate the staining of the polyamide face pile by the jutebacking.

Another object is the provision of a dyeing process which provides aconsiderable saving in steam, time and labor as compared to prior artprocesses, which is simple in its application and which will make itpossible to effectively dye polyamide carpet yarns and polyamide carpetfabrics having a jute backing with selected acid dyes at comparativelylow temperatures.

Yet another object is the provision of a dyeing process which willminimize the distortion of the face pile and thus improve the physicalappearance of the carpet fabric.

Still another object is the provision of dyeing compositions capable ofeffectively dyeing polyamide carpet yarns and polyamide carpets with ajute backing.

Other objects of the present invention will become apparent in thecourse of the following specification.

In the accomplishment of the objectives of the present invention it wasfound necessary to employ a combination of the following two components:

3,472,607 Patented Oct. 14, 1969 The first component consists of aleveling agent having moderately retarding properties.

The second component consists of a buffer salt which is capable ofcontrolling the pH during the dyeing process to between 5.5 and 7 .5.

FIRST COMPONENT The leveling agent used in the process of the presentinvention has components which are selected from:

(a) An ethoxylated fatty amine having 5 to 50 mols ethylene oxide.

(b) An ethoxylated fatty alcohol having 10 to 50 mols ethylene oxide.

The preferred components are an ethoxylated fatty amine having 10 to 20mols ethylene oxide and an ethoxylated fatty alcohol having 20 to 30mols ethylene oxide.

The preferred proportions are 3 to 5 parts of the fatty amine to 5 partsof the ethoxylated fatty alcohol.

SECOND COMPONENT The buffer salt used in the process of the presentinvention must control the pH during dyeing to between 5.5 and 7.5 andpreferably between 6.0 and 7.0. It was found that this is most importantto achieve the desired results. The components of the buffer salt are analkali metal salt of phosphoric acid and an alkali metal salt of avolatile acid such as acetic or formic acid.

The preferred components are monosodium or monopotassium phosphate andsodium or potassium formate.

The proportion of leveling agent to buffer salt may be from 0.5 to 3.0parts leveling agent to 2 to 5 parts buffer salt, the preferredproportion being from 1 to 2.5 parts leveling agent to 3 to- 4.25 partsbuffer salt.

The process of the present invention may be carried out at a temperaturerange of F.180 F., but the preferred range is F. F. The bath ratio usedin practicing the invention may be from 20:1 up to 60:1 and preferablyis from 25:1 to 40:1.

The following examples of the products and processes of the presentinvention are given solely by way of illustration and not by way oflimitation:

FIRST COMPONENT Ethoxylated stearyl+palmityl alcohol (20 mols)- 25 Eachproduct is made up to 100 parts with water after adjusting pH to about7.0 with a small amount of acetic acid.

Percent (OWF Monosodium phosphate 2.0 Sodium formate 1.0 Product 3 2.0

A piece of pre-scoured carpet of nylon 66 staple (Du Pont Type 814) withjute backing was entered and run for about minutes.

Pro-dissolved dyes were then added:

Percent (OWF) Telon Yellow BL (Verona Dyestulf) 1 0.180 Telon Red BL(Verona Dyestuff) 1 0.096 Telon Blue BL (Verona Dyestuff) 1 0.030

30:1 dye bath was prepared at 90 F. with:

Percent (OWF) Monosodium phosphate 2.0 Sodium formate 1.0 Product 2 2.5

Pre-scoured staple nylon 66 carpet (type 814 Du Pont) was entered andworked for about 10 minutes. Pre-dissolved dyes:

Percent (OWF) Nylomine Yellow GS (I.C.I. Organics) 0.230 Nylomine Red2BS (I.C.I. Organics) 0.096

Acid Blue 25 0.030

These dyes have no color index numbers.

Bath was heated gradually to 150 F. and dyeing continued at 145-150 F.for one hour. pH of bath at completion of dyeing6.2. Resultant dyeingwas very level, nylon pile face was thoroughly penetrated, there waspractically no distortion of pile or staining by jute backing.

Example III Dyeing was carried out on pre-scoured carpet type 814 (DuPont) in the same manner as in Example IV, except that 0.5% (OWF)monosodium phosphate and 2.0% (OWF) sodium formate were used. Initial pHof dyebath6.9. Dyeing was carried out at 155 -160 F. for 1.25 hours. pHof dyebath after completion of dyeing6.8. Resultant dyeing was level,well penetrated and otherwise similar to Example IV.

Example IV 40:1 dye bath was prepared at 100 F. with:

Percent (OWF) Monosodium phosphate 3.0 Sodium formate 1.0 Product 1 1.25

Pre-scoured nylon carpet, type 814 (Du Pont), was entered and worked forabout 10 minutes.

Pre-dissolved dyes:

Percent (OWF) Acid Yellow 114 0.063 Acid Black 64 0.0063 Acid Brown 450.2700

were added, bath heated gradually to 180 F. and dyeing continued at thistemperature for one hour. Bath was cooled, carpet rinsed thoroughly anddried. Resultant dyeing was level, there was very little distortion ofthe pile and minimum staining by the jute. pH of dyebath aftercompletion of dyeing-60.

Example V 25 :1 dye bath was prepared at F. with:

Percent (OWF) Monosodium phosphate 4.0 Sodium formate 0.25 Product 2 1.0

Staple nylon carpet (type 814 Du Pont) was entered and worked for aboutten minutes. 2.0% (OWF) Pontacyl Red LN, pre-dissolved, was then added,bath heated gradually to 155 F. and dyeing continued at 155-160 F. for1.5 hours. Bath was cooled, dropped, carpet rinsed thoroughly and dried.Resultant dyeing was bright. Pile was thoroughly penetrated, and thefastness properties were satisfactory. pH after dyeing6.1.

It is apparent that the above described examples were given solely byway of illustration and not by way of limitation and that they aresubject to many variations and modifications within the scope of thepresent invention. All such variations and modifications are to beincluded within the scope of the present invention.

What is claimed is:

1. The process which comprises dyeing jute backed nylon carpets withacid dyes at a temperature range of F. to 180 F. and within a controlledpH range of 5.5 to 7.5 in the presence of a leveling agent comprising anethoxylated fatty amine having 5 to 50 mols ethylene oxide and anethoxylated fatty alcohol having 10 to 50 mols ethylene oxide, theproportions being 3 to 5 parts of the fatty amine to 5 parts fattyalcohol, and a buffer salt controlling said pH range of 5.5 to 7.5 andin which the dye bath is acidic at the completion of dyeing, whereby thepile of the dyed carpet is rendered substantially free from distortionand staining by the jute.

2. The process in accordance with claim 1, wherein the buffer saltcomprises an alkali metal salt of phosphoric acid and an alkali metalsalt of a volatile acid selected from the group consisting of acetic andformic acids, the proportion of leveling agent to buffer salt being 0.5to 3.0 parts leveling agent to 20 to 5.0 parts buffer salt.

3. The process in accordance with claim 1, wherein the temperature rangeis F. to F.

4. The process in accordance with claim 1, wherein the pH range is 6.0to 7.0.

5. The process in accordance with claim 1, wherein the dyeing takesplace in a beck or winch.

6. A preparation for a dye bath for a jute backed polyamide carpet,comprising a leveling agent comprising an ethoxylated fatty amine having5 to 50 mols ethylene oxide and an ethoxylated fatty alcohol having 10to 50 mols ethylene oxide, the proportions being 3 to 5 parts of thefatty amine to 5 parts fatty alcohol, and a buffer salt controlling thepH range to 5.5 to 7.5, the proportion of leveling agent to buffer saltbeing 0.5 to 3.0 parts leveling agent to 2.0 to 5.0 parts buffer salt.

7. A preparation in accordance with claim 6, wherein the leveling agentcomprises an ethoxylated fatty amine having 10 to 20 mols ethylene oxideand an ethoxylated fatty alcohol having 20 to 30 mols ethylene oxide,the proportions being 3 to 5 parts of the fatty amine to 5 parts of theethoxylated fatty alcohol.

8. A preparation in accordance with claim 6 wherein said buffer saltcomprises an alkali metal salt of phosphoric acid and an alkali metalsalt of a volatile acid selected from the group consisting of acetic andformic acids.

9. A preparation in accordance with claim 6, wherein said buffer saltcomprises a phosphate selected from the group consisting of monosodiumphosphate and monopotassium phosphate and a formate selected from thegroup consisting of sodium formate and potassium formate, theproportions being 0.5 to 4 parts of the alkali phosphate and 0.25 to 2parts of the alkali formate.

References Cited UNITED STATES PATENTS 6 OTHER REFERENCES E. F.Schnider, Proceed. Am. Ass. Textile Chem. & C0l., Am. Dyestuif Reporter,May 13, 1963, p. 370, p. 375, p. 376.

NORMAN A. TORCHIN, Primary Examiner Innarone.

SaperS et J. E. CALLAGHAN, Assistant Examiner Casty 821 Ortheil s 14 us.01. X.R. Gift et a1. 855 s- 55

